Study Of Acrylamide-Based Block Copolymers Via RAFT Polymerization

The study on CO₂separation is one of the most important subjects inrecent years, and the facilitated transport membrane with fixed carrier ismost interesting kind of separation membranes for this purpose. Recentlymuch attention has been paid to reversible addition-fragmentation chaintransfer （RAFT） mediated living free radical polymerization in polymerchemistry. Based on the RAFT polymerization methods, we synthesisedsome new kinds of membrane materials. The immobilized carrier CO₂promote transfer separation membrane were prepared.S-l-Dodecyl-S′-（,′-dimethyl--acetic acid） trithiocarbonate（MTTCD）, S, S′-bis （2-hydroxyethyl-2′-dimethyla crylate） trihiocarbonate（BDATC）,2-cyanoprop-2-yl-dithiobenzoate （CPDB） were prepared.Macromolecules chain transfer agents （PMAM-CTA） weresynthesized through the reversible addition fragmentation chain transferpolymeri zation （RAFT） by using MTTCD and BDATC as the chaintransfer agent, methacrylamide （MAM） as the first polymerizationmonomer. The derived block copolymer （PMAM-b-PNVP） was preparedby using the above obtained polymer as macromolecular RAFT agent andNVP as second polymerization monomer. N-vinyl-γ-sodiumaminobutyrate-sodium methacrylate copolymer （VSA-MSA） containing-NH2and-COOH as the CO₂facilitated carrier, a kind of new fixed carrier membrane material for CO₂separation, was synthesized by hydrolysis ofthe resulted PMAM-b-PNVP.Macromolecules chain transfer agents polymethyl methacrylate（PMMA-CTA） were synthesized through the reversible additionfragmentation chain transfer （RAFT） polymerizationby using MTTCD,BDATC, CPDB as the chain transfer agents, Methyl methacrylate （MMA）as the first monomer． The derived well-controlled block copolymerPMMA-b-PDMAEMA was successfully prepared by using the aboveobtained polymer as macromolecular RAFT agent and N,N-dimethylaminoethy methacrylate （DMAEMA） as second monomer.The chemical composition and structure of PMAM-CTA,PMAM-b-PNVP, VSA-MSA, PMMA-CTA and PMMA-b-PDMAEMAwere analyzed by FTIR,1HNMR, XRD and DSC, the molecular weight andpolydispersity index was analyzed by GPC.The VSA-MSA/PSF composite membranes were prepared and theirmicrostructures were analyzed by SEM. The CO₂and N₂permeationperformance were tested at different pressure. The results showed that theresulted composited membrane had a CO₂permeation rate of1.2×10^-4cm³（STP） cm^-2s^-1cmHg^-1and a N32permeation rate of4.06×10^-5cm^STPcm-2s^-1cmHg^-1permeation rate of and an ideal CO₂/N₂selectivity of40at afeed gas pressure of7.6cmHg and30℃.The PMMA-b-PDMAEMA/PSF composite membranes were preparedand their microstructures were analyzed by SEM. The CO₂and N₂permeation performance were tested at different pressure. The resultsshowed that the resulted composited membrane had a CO₂permeation rateof3.68×10^-5cm³（STP） cm-2s^-1cmHg^-1and a N₂permeation rate of1.78×10^-7cm³（STP） cm-2s^-1cmHg^-1permeation rate of and an ideal CO₂/N₂selectivity of200at a feed gas pressure of7.6cmHg and30℃.